A hope for paralyzed patients- New technology on its way

A new system have been developed at Duke University in North Carolina. A group of researchers led a study in which monkeys have learned to control the movement of both arms on an avatar using their brain activity. This study can be a major break through especially in helping paralysed or spinal cord injured patients who needs assist. They are currently working to develop tools help restore such patient's mobility and sense of touch by connecting their brains with assistive devices.  

To perform this task, researchers recorded nearly 500 neurons from multiple areas in both cerebral hemispheres of the animal's brains, the largest number of neurons recorded and reported to date. The brain-machine interface approach, pioneered at the Duke University Centre for Neuronengineering in the early 2000, holds promise for reaching this goal. 

"Bimanual movements in our daily activities--from typing on a keyboard to opening a can--are critically important," said senior Miguel Nicolelis, M.D.,Ph.D, professor of neurobiology at Duke University School of Medicine. "Future brain-machine interfaces aimed at restoring mobility in humans will have to incorporate multiple limbs to greatly benefit severely paralysed patients." 

Nicolelis and his team did a lot of studies on cortical recordings to see whether it could provide sufficient signals to brain-machine interfaces to accurately control bimanual movements. The monkeys in their experiment were trained in a virtual environment within which they viewed realistic avatar arms on a screen and were encouraged to place their virtual hands on specific targets in a bimanual motor task. The monkeys first learnt to control the avatar arms using a pair of joysticks, then they were able to learn to use just their brain activity to move both avatar arms without moving their own arms. While the animals were developing their skills the researchers observed widespread plasticity in cortical areas of their brains. These results suggest that the monkeys brains may incorporate the avatar arms into their internal image of their bodies. The researchers also found that cortical regions showed specific patterns of neuronal electrical activity during bimanual movements that differed from the neuronal activity produced for moving each arm separately.

Different stages of virtual hand move-stage1
Monkey's mind trying to move the hands of the virtual avatar on the object displayed

Different stages of virtual hand move-stage-2
Based on different shapes appearing on the display, the monkeys were able to control their virtual hands to the displayed object to hold them or to move to their position

Different stages of virtual hand move-stage-3

The studies shows that very large neuronal ensembles--not single neurons--define the underlying physiological unit of normal motor functions. Small neuronal samples of the cortex may be insufficient to control complex motor behaviours using a brain-machine interface. 

Currently Nicolelis is incorporating the study's findings into the Walk Again Project, an international collaboration working to build a brain-controlled neuroprosthetic device. The Walk Again Project plans to demonstrate its first brain-controlled exoskeleton during the opening ceremony of the 2014 FIFA World Cup.